JP2000264952A - Epoxy resin mixture and epoxy resin composition for powder coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin mixture which has a crystallizing property at ordinary temperature, has excellent handling workability, can express an excellent low viscosity in a melted state and is useful as a powder coating material, by compounding a tetrabromobisphenol A type epoxy resin and a bisphenol type epoxy resin in a specific ratio. SOLUTION: This epoxy resin mixture comprises (A) 40-95 pts.wt. of a tetrabromobisphenol A type epoxy resin of formula I [(n) is 0-1 on the average] and (B) 5-60 pts.wt. of a 4,4'-bisphenol type epoxy resin of formula II [(m) is 0-0.5 on the average]. The mixture is preferably obtained by reacting a mixture of tetrabromobisphenol A with 4,4'-bisphenol with an epihalohydrin in an amount of 4-40 moles per mole of the mixture of the phenol compounds in the presence of an alkali metal hydroxide. The mixture of the tetrabromobisphenol A with the 4,4'-bisphenol is prepared so as to finally give the above ratio. The obtained mixture preferably has a melt viscosity of <=0.4 P at 150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an epoxy resin mixture which is crystalline at room temperature and therefore excellent in handling workability, and has an extremely low viscosity in a molten state. The epoxy resin of the present invention is suitable for powder coatings because it has excellent gap filling properties because it has excellent viscosity and extremely low viscosity in the molten state, and the resulting coating film has good smoothness and adhesion of the coated surface. The present invention relates to an epoxy resin composition using a mixture.

[0002]

2. Description of the Related Art Powder compositions, such as powder coatings, are replacing conventional solvent-based coatings in a wide range of applications as pollution-free, resource-saving and energy-saving coatings. However, general powder coatings have a high viscosity when melted, so they have the advantage of being able to finish a thick film with a single coating operation.On the other hand, they have good wettability with objects to be coated, Gap filling,
There is a drawback that the surface smoothness during thin film coating is poor,
In addition, with the recent expansion of applications, there has been a demand for improvements in the above-mentioned defects as well as improvements in adhesion and moisture resistance, and the development of new materials to meet these needs has been required.
Epoxy resins, on the other hand, come in a variety of forms, from liquid to solid, and can exhibit a variety of hardened physical properties depending on the type and type of hardener to be mixed. It is used in a wide range of fields such as insulation. Among these epoxy resins, epoxy resins such as solid bisphenol A type, tetrabromobisphenol A type, and novolak type are known as those used for powder coatings. However, since such a conventional epoxy resin generally has a somewhat large molecular weight, the melt viscosity is high, and when used in a powder coating, the wettability with the article to be coated, the gap filling property, It has poor surface smoothness during thin film coating and is not suitable for application to complex structures or filling in narrow voids. Therefore, it is conceivable to reduce the molecular weight in order to reduce the melt viscosity. However, in this case, the epoxy resin becomes liquid or semi-solid, and if liquid, semi-curing is required for powdering,
In this case, there is a problem that the melt viscosity is increased by increasing the molecular weight, and in the case of semi-solid, there is a problem that the handling efficiency is extremely poor due to blocking of the epoxy resin itself. As means for solving these problems, Japanese Patent Application Laid-Open No.
No. 248725 discloses 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5' as an epoxy resin.
Although an epoxy resin component composed of tetramethylbiphenyl is used, a composition of the epoxy resin with a curing agent or the like becomes a solid having a low softening temperature and is not sufficient in terms of blocking resistance. From the tetrabromobisphenol A type epoxy resin, a crystalline epoxy resin having an excellent blocking resistance and a low melt viscosity can be obtained by an operation such as recrystallization, but a complicated recrystallization operation significantly deteriorates economic efficiency. Further, it is advantageous to use a low molecular weight epoxy resin for the adhesion to the object to be coated,
This is not practical because the above-mentioned disadvantage of poor blocking resistance at room temperature cannot be solved.

[0003]

The problem to be solved by the present invention is to solve the above-mentioned problem. Since it is crystalline at normal temperature, it has excellent handling workability and has extremely low viscosity in a molten state. The epoxy resin mixture, which is solid at room temperature, has excellent blocking resistance, and has extremely low viscosity in the molten state, so it has excellent gap filling properties, and the obtained coating film has good smoothness and moisture resistance of the coated surface. Therefore, it is an object of the present invention to provide an epoxy resin composition suitably used for powder coatings.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found an epoxy resin composition for powder coatings that can achieve these objects, and have reached the present invention. That is, the present invention provides: “1. An epoxy resin mixture comprising the following components. (A) From 40 parts by weight to 95 parts by weight of a tetrabromobisphenol A-type epoxy resin represented by the general formula (I). I)

[0005]

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(Where n is an average number of 0 to 1) (b) 5,4 to 60 parts by weight of 4,4'-biphenol type epoxy resin represented by the general formula (II) . (B) General formula (II)

[0007]

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(Where m is a number from 0 to 0.5 on average). In the epoxy resin mixture according to item 1,
The proportion of not less than 40 parts by weight and not more than 95 parts by weight of the tetrabromobisphenol A type epoxy resin after epoxidation, and not less than 5 parts by weight and not more than 60 parts by weight of the 4,4'-biphenol type epoxy resin as the whole or part of the epoxy resin mixture. A mixture of tetrabromobisphenol A and 4,4'-biphenol adjusted as described above is reacted with 4 to 40 mol of epihalohydrin per mol of the mixture of the phenol compound in the presence of an alkali metal hydroxide. An epoxy resin mixture characterized by using the prepared epoxy resin mixture. 3. 3. The epoxy resin mixture according to item 1 or 2, wherein the melt viscosity at 150 ° C. is 0.4 P or less. 4. 4. An epoxy resin composition for powder coatings, comprising the epoxy resin mixture according to any one of items 1 to 3 and a curing agent for epoxy resin as essential components. 5. 5. The epoxy resin composition for powder coatings according to item 4, wherein the curing agent for epoxy resin is an acid-based curing agent and / or an amine-based curing agent. About.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The epoxy resin mixture of the present invention comprises:
(A) A certain amount of 4,4'-biphenol type epoxy resin having a high melting point and a low melt viscosity is added to a tetrabromobisphenol A type epoxy resin to give a crystallinity at room temperature, thereby reducing the crystallinity. It is melt-viscosified. Further, the epoxy resin composition for powder coating of the present invention,
This is a composition using the epoxy resin mixture of the present invention. Even when the composition is prepared by mixing with various curing agents, the composition is solid and has excellent blocking resistance. In addition, since the epoxy resin composition for a powder coating of the present invention has a low melt viscosity, a coating film formed using the same has excellent smoothness and adhesion.

The (a) tetrabromobisphenol A type epoxy resin, which is one component of the epoxy resin mixture of the present invention, is obtained by reacting tetrabromobisphenol A with epihalohydrin in the presence of an alkali to form an epoxy resin. The structure is represented by the general formula (I), and in order to maintain a low melt viscosity, the average value of n in the formula is preferably from 0 to 1, more preferably from 0 to 0.4,
More preferably, it is 0 to 0.1.

The reaction between tetrabromobisphenol A and epihalohydrin can be carried out by a known method, and a typical embodiment will be described in detail below. First, tetrabromobisphenol A is dissolved in an amount of epihalohydrin corresponding to 4 to 40 mol per mol to form a uniform solution. Then, while expanding the solution, 1.8 to 4 moles of an alkali metal hydroxide per mole of tetrabromobisphenol A is added as a solid or an aqueous solution and reacted. This reaction can be carried out under normal pressure or reduced pressure, and the reaction temperature is usually 30 to 15 when the reaction is carried out under normal pressure.
0 ° C., and 30 to 80 ° C. in the case of a reaction under reduced pressure. In the reaction, a reaction solution is azeotropically maintained while maintaining a predetermined temperature as needed, and a condensate obtained by cooling a volatilized vapor is separated into oil / water, and an oil component from which water has been removed is returned to the reaction system. To dehydrate. The addition of the alkali metal hydroxide is intermittently or continuously added in small amounts over 1 to 8 hours in order to suppress a rapid reaction. The total reaction time is usually
1 to 10 hours. After completion of the reaction, insoluble by-product salts are removed by filtration or removed by washing with water, and unreacted epihalohydrin is removed by distillation under reduced pressure to obtain the desired epoxy resin. Epichlorohydrin or epibromohydrin is usually used as epihalohydrin in this reaction. Sodium hydroxide or potassium hydroxide is usually used as the alkali metal hydroxide.

In this reaction, quaternary ammonium salts such as tetramethylammonium chloride and tetraethylammonium bromide; tertiary amines such as benzyldimethylamine and 2,4,6-tris (dimethylaminomethyl) phenol; Catalysts such as imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole; phosphonium salts such as ethyltriphenylphosphonium iodide; and phosphines such as triphenylphosphine may be used. Further, in this reaction, alcohols such as ethanol and isopropanol;
Ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and ethylene glycol dimethyl ether; glycol ethers such as methoxypropanol;
An inert organic solvent such as an aprotic polar solvent such as dimethylsulfoxide and dimethylformamide may be used. Further, when the amount of the saponified halogen in the epoxy resin obtained as described above is too large, the epoxy resin can be obtained by reprocessing to sufficiently reduce the amount of the saponified halogen. In other words, the crude epoxy resin was converted to isopropanol, methyl ethyl ketone, methyl isobutyl ketone,
Redissolve in an inert organic solvent such as toluene, xylene, dioxane, methoxypropanol, dimethylsulfoxide, etc., add an alkali metal hydroxide as a solid or aqueous solution, and re-close the ring at a temperature of about 30 to 120 ° C for 0.5 to 8 hours. After the reaction, excess alkali metal hydroxide and by-product salts are removed by washing with water or the like, and the organic solvent is removed by distillation under reduced pressure to obtain a purified epoxy resin.

The (4) -biphenol type epoxy resin (b), which is another component of the epoxy resin mixture of the present invention, comprises (a) tetrabromobisphenol in the presence of an alkali and 4,4'-biphenol and epihalohydrin. The epoxy resin is reacted in the same manner as the A-type epoxy resin. Its structure is represented by the general formula (II),
In order to maintain a low melt viscosity, the average value of m in the formula is 0 to
0.5, more preferably 0 to 0.
3.

The epoxy resin mixture of the present invention comprises (a) a tetrabromobisphenol A type epoxy resin and (b)
The 4,4'-biphenol-type epoxy resin may be separately produced or obtained and mixed and used, or the raw materials, tetrabromobisphenol A and 4,4'-biphenol, may be contained in the same container. May be used as a mixture of respective epoxy resins obtained by simultaneously reacting with epihalohydrin. In order to obtain an epoxy resin having good compatibility with a curing agent or the like, the latter method is preferable. When the latter method is used, (a) after epoxidation
Tetrabromobisphenol A type epoxy resin and (b)
The mixing ratio of the 4,4'-biphenol type epoxy resin is prepared in advance so that the mixing ratio of each raw material is (a) 40 to 95 parts by weight and (b) 5 to 60 parts by weight. Alternatively, it is necessary to add one or both epoxy resins after the epoxidation so as to have a predetermined ratio.

The mixing ratio of (a) tetrabromobisphenol A type epoxy resin and (b) 4,4'-biphenol type epoxy resin is as follows: (a) 40 to 95 parts by weight of tetrabromobisphenol A type epoxy resin. (B) 4,4'-biphenol type epoxy resin 5
Not less than 60 parts by weight and preferably not less than 60 parts by weight and not more than 90 parts by weight of (a) tetrabromobisphenol A type epoxy resin, and not less than 10 parts by weight of (b) 4,4'-biphenol type epoxy resin. It is 40 parts by weight or less. (B) If the amount of the 4,4'-biphenol type epoxy resin used is too small, the melt viscosity increases. (B) 4,
If the amount of the 4'-biphenol type epoxy resin is too large, the melt viscosity will be low, but the quick curing property will be poor. The melt viscosity at 150 ° C. of the epoxy resin mixture of the present invention is 0.1.
4 or less, preferably 0.3 or less. In order to achieve this melt viscosity, it is necessary to adjust reaction conditions such as the molar ratio of epihalohydrin to the starting phenol compound. The epoxy resin mixture thus obtained is
Since it is crystalline at normal temperature, it has excellent handling workability and has extremely low viscosity in a molten state, so that it can be suitably used for epoxy resin applications requiring fluidity.

In the epoxy resin composition for powder coating of the present invention, as the curing agent used together with the epoxy resin mixture of the present invention, various acid-based and / or amine-based curing agents conventionally known as epoxy resin curing agents are used. Agents can be used. Examples of the acid-based curing agent include acid anhydrides and polyhydric phenols. As the acid anhydride, for example, phthalic anhydride, trimellitic anhydride,
Aromatic carboxylic anhydrides such as pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol trimellitic anhydride, biphenyltetracarboxylic anhydride, and aliphatic carboxylic acids such as azelaic acid, sebacic acid and dodecanedioic acid Alicyclic carboxylic acids such as anhydrides, tetrahydrophthalic anhydride, hexahydroanhydride, methyltetrahydrophthalic anhydride, methylhexahydroanhydride, nadic anhydride, hetanoic anhydride, hymic anhydride, etc. Anhydrides and the like.

As polyhydric phenols, catechol,
Resorcinol, hydroquinone, pyrogallol, bisphenol A, bisphenol F, biphenol, tetrabromobisphenol A, trishydroxyphenylmethane, phenol, cresols, butylphenols,
Examples include novolak resins, aralkyl polyphenols, dicyclopentadiene polyphenols, terpene polyphenols, and the like, made from various phenols such as octylphenols, bisphenol A, bisphenol F, bisphenol S, tetrabromobisphenol A, and naphthols. Other usable acid-based curing agents include Bronsted acid salts such as aliphatic sulfonium salts and aromatic sulfonium salts, resols, adipic acid, sebacic acid, terephthalic acid, trimellitic acid and carboxyl group-containing polyesters. And polycarboxylic acids.

Examples of the amine-based curing agent include amines and salts thereof. As amines, for example, metaphenylenediamine, diaminodiphenylmethane, aromatic amines such as diaminodiphenylsulfone, bis (4-aminocyclohexyl) methane, bis (aminomethyl) cyclohexane, 3,9-bis (3-
Alicyclic amines such as aminopropyl) -2,4,8,10-tetraspiro [5,5] undecane, benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,
0) Undecene-7,1,5-diazabicyclo (4,
Tertiary amines such as (3,0) nonene-7 and salts thereof.

[0019] Other usable amine curing agent, 2-methylimidazole, 2-ethyl-4-methylimidazole and 2-phenylimidazole, etc. imidazole compounds of and salts thereof, BF ₃ complex compounds of amines, dicyandiamide And organic acid hydrazides such as adipic dihydridide and phthalic dihydridide. These epoxy resin curing agents are:
From the viewpoint of workability, a material having a softening point or melting point of 50 ° C. or more is optimal, and two or more of these may be used in combination.

These hardeners are used in a ratio of 0.5 to 1.5 equivalents of a hardener active group per equivalent of epoxy group contained in the epoxy resin mixture of the present invention. The imidazole is used in a proportion of 0.1 to 5 parts by weight based on 100 parts by weight of the epoxy resin mixture of the present invention. By selecting the type of the above-mentioned curing agent, various functions can be added in addition to the excellent gap filling property exhibited by the characteristics of the epoxy resin mixture. For example, dicyanamide improves the long-term storage stability of the powder composition, acid anhydride and phenol resin improve the heat resistance of the cured product, and aromatic amine and linear phenol resin increase the flexibility of the cured product. In addition, imidazoles are provided with characteristics such as quick curability, and these characteristics can be combined by using these curing agents in combination.

The epoxy resin composition for powder coating of the present invention comprises the epoxy resin mixture of the present invention, that is, (a) a tetrabromobisphenol A type epoxy resin and (b) 4,4
Epoxy resins other than the 4'-biphenol type epoxy resin can be mixed if necessary.
The amount is preferably 100 parts by weight or less, more preferably 50 parts by weight or less based on 0 parts by weight. If the proportion of the other epoxy resin is too large, the effect of the present invention cannot be sufficiently exhibited. Other epoxy resins that can be mixed include bisphenol A, bisphenol F,
Various phenols such as bisphenol AD, 3,3 ', 5,5'-tetramethylbiphenol, terpene diphenol, hydroquinone, dibutylhydroquinone, resorcinol, dihydroxydiphenylether, dihydroxynaphthalene, and various phenols and formaldehyde, acetaldehyde; Epoxy resins, diaminophenylmethane, aminophenol, xylene produced from various phenolic compounds such as polyhydric phenol resins obtained by condensation reaction with various aldehydes such as crotonaldehyde, hydroxybenzaldehyde, glyoxal and epihalohydrin Epoxy resins produced from various amine compounds such as diamines and epihalohydrin, and various carbohydrates such as methylhexahydroxyphthalic acid and dimer acid. And acids, and epoxy resins produced from an epihalohydrin.

The epoxy resin composition for powder coatings of the present invention may optionally contain a curing accelerator suitable for the type of curing agent used in order to accelerate the curing. As such a curing accelerator, any known curing accelerator can be used.For example, when acid anhydrides or polyhydric phenols are used as the curing agent, tertiary compounds such as imidazole, dicyandiamide, imidazoline, and benzyldimethylamine are used. Examples include amines, phosphine compounds such as triphenylphosphine, and tris (dimethoxyphenyl) phosphine. When an aromatic amine is used as a curing agent, examples include basic compounds such as imidazole, boron trifluoride, and derivatives thereof. . The curing accelerator used here varies depending on the type and purpose of use of the curing agent, but is usually used in a ratio of 0.1 to 5 parts by weight based on 100 parts by weight of the epoxy resin. The epoxy resin composition for powder coating of the present invention, if necessary, a filler, a reinforcing agent, a coloring agent,
Pigments, flame retardants, flame retardant aids, diluents, synthetic resins and the like can be appropriately added and blended.

The method for producing a powder coating using the epoxy resin composition of the present invention comprises a dry blending method, a melt blending method, and a pressure blending method using the above-described epoxy resin mixture of the present invention, a curing agent and necessary additives. In particular, in order to sufficiently mix the individual components obtained by mixing and pulverizing and classifying by a known method such as the above, a melt blending using a heating kneader or an extruder is preferable. The particle size of the powder coating is preferably small so as not to impair the appearance of the coating film, and is usually preferably about 1 to 80 μm. The epoxy resin composition thus obtained is excellent in blocking resistance because it is a solid at ordinary temperature, and has excellent gap filling properties because it has a very low viscosity in a molten state, and has good wettability to the object to be coated. It has good thin film coating properties and can be suitably used for powder coatings.

[0024]

EXAMPLES The following examples illustrate the production of the epoxy resin mixture of the present invention, and further illustrate examples and comparative examples of the epoxy resin composition for powder coating of the present invention.

Examples 1 to 3 of Epoxy Resin Mixtures In a 5 L four-necked flask equipped with a thermometer, a stirrer, and a condenser, 1270 g of phenolic compound, epichlorohydrin and 494 g of isopropanol of the type and amount shown in Table 1 were placed. After charging and heating to 50 ° C. to dissolve uniformly, 217 g of a 48.5% by weight aqueous sodium hydroxide solution was added.
Was added dropwise over 2 hours. During this time, the temperature was gradually raised so that the temperature in the system reached 70 ° C. after completion of the dropwise addition. Then 7
The mixture was kept at 0 ° C. for 30 minutes to complete the reaction, and by-product salts and excess sodium hydroxide were removed by washing with water. Subsequently, excess epichlorohydrin and isopropanol were distilled off from the product under reduced pressure to obtain a crude epoxy resin. This crude epoxy resin was dissolved in 1000 g of methyl isobutyl ketone, and a 48.5% by weight aqueous sodium hydroxide solution 1 was added.
0 g was added and reacted at a temperature of 85 ° C. for 1 hour. Thereafter, an aqueous solution of sodium phosphate monobasic was added to the reaction solution to neutralize excess sodium hydroxide and washed with water to remove by-product salts. Next, methyl isobutyl ketone was completely removed under reduced pressure to obtain the desired epoxy resin. Table 1 shows the composition, epoxy equivalent weight and melt viscosity of these epoxy resin mixtures.

[0026]

[Table 1]

(Note) * 1: Calculated from raw material charge * 2: Cone & plate viscometer 150 ° C

Composition of Epoxy Resin for Powder Coating Example 4
To 9 and Comparative Examples 1 to 3 As the epoxy resin mixture of the present invention, each epoxy resin mixture produced in Examples 1 to 3, a commercially available solid bisphenol A type epoxy resin, a commercially available tetrabromobisphenol A type epoxy resin, and a commercially available epoxy resin mixture A bisphenol A novolak resin, tetrahydrophthalic anhydride, and dicyandiamide as epoxy resin curing agents; and triphenylphosphine and 2-ethyl- as curing accelerators.
4-methylimidazole and silica powder as a filler were preliminarily mixed at the ratios shown in Table 2. Next, the mixture was melt-kneaded at 115 ° C. using an extruder, cooled, and then pulverized with a hammer mill to prepare a powder coating composition having a particle size of 1 to 106 μm as a main component using a standard sieve. As a result of examining the melt viscosity and the blocking resistance of each of the prepared powder coating materials, the results are as shown in Table 2.
Each of the powder coatings Nos. To 9 had lower melt viscosity and excellent blocking resistance than the powder coatings of Comparative Examples 1 to 3.
Further, these powder coating compositions are coated on a steel plate heated to 180 ° C. by using an electrostatic coating machine to perform coating.
Post-curing was performed in an oven at 00 ° C. for 20 minutes to obtain a coating film specimen having a coating film thickness of 80 to 120 μm. Table 2 shows the results of examining the coating film performance of the obtained coating film specimen.
Each of the powder coatings of Examples 4 to 9 had a smooth surface similarly to each of the powder coatings of Comparative Examples 1 to 3, but had excellent adhesion.

[0029]

[Table 2]

(Note) In the table, the amounts are all parts by weight.

(Explanation of Measurement of Physical Properties in Table 2) The melt viscosity is defined as the melt viscosity at 150 ° C. of each of the powder compositions in Table 2 excluding the curing accelerator and the filler, and the cone and plate viscosity. It was measured using a meter. For each powder coating in Table 2, 40 ° C.
The state of blocking when left for one week in a constant temperature bath was evaluated according to the following criteria. ：: Fluid without forming a state △: Lump does not form but does not flow ×: The whole becomes a lump and does not flow The coating surface is the coating film of the obtained coating film specimen at room temperature Was visually inspected. Adhesion was evaluated on the obtained coating film test piece according to a base line method (JISK-5400 8.5.1.).

(Explanation of each material used in Table 2) Epoxy resin A: Epicoat 1001 (solid bisphenol A type epoxy resin), manufactured by Yuka Shell Epoxy, W
PE466g / eq. Epoxy resin B: Epicoat 5050 (solid bisphenol A type epoxy resin), manufactured by Yuka Shell Epoxy, W
PE 390 g / eq. Epoxy resin C: Epicoat YX4000 (tetramethyl biphenyl type epoxy resin), manufactured by Yuka Shell Epoxy, WPE 186 g / eq. Curing agent D: dicyandiamide Curing agent E: Epicure YLH129 (bisphenol A
Novolak type resin), manufactured by Yuka Shell Epoxy Co., Ltd., having a phenolic hydroxyl equivalent of 120 g / eq. Curing agent F: tetrahydrophthalic anhydride Curing accelerator G: 2-ethyl-4-methylimidazole Curing accelerator H: triphenylphosphine

[0033]

According to the present invention, the epoxy resin mixture of the present invention is crystalline at room temperature, so that it has excellent handling workability and has a very low viscosity in a molten state. Epoxy resin compositions for coatings are solid at room temperature and have excellent blocking resistance, and in the molten state, have extremely low viscosity, so they have excellent gap filling properties, and the resulting coating film has smoothness and adhesion of the coating surface. Good.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 5/03 C09D 5/03 163/00 163/00 F term (Reference) 4J036 AA05 AD07 AD09 DA01 DB06 DB15 DC02 DC31 DC35 DC41 FB07 FB11 GA03 GA06 GA19 JA03 KA05 4J038 DA062 DB052 DB131 JA42 JA64 JB01 JC17 KA03 NA01 NA10 NA12 PA02

Claims (5)

[Claims] 1. An epoxy resin mixture comprising the following components: (A) 40 to 95 parts by weight of a tetrabromobisphenol A type epoxy resin represented by the general formula (I). General formula (I) (In the formula, n is a number of 0 to 1 on average.) (B) 5,4 to 60 parts by weight of 4,4′-biphenol type epoxy resin represented by the general formula (II). Formula (II) (Where m is a number from 0 to 0.5 on average) 2. The epoxy resin mixture according to claim 1, wherein the total amount or a part of the epoxy resin mixture is from 40 parts by weight to 95 parts by weight of the epoxidized tetrabromobisphenol A-type epoxy resin. ′
A mixture of tetrabromobisphenol A and 4,4'-biphenol adjusted to have a proportion of 5 to 60 parts by weight of a biphenol type epoxy resin, and 4 to 40 moles of epihalohydrin per mole of the mixture of the phenolic compound Characterized by using an epoxy resin mixture obtained by reacting the above with an alkali metal hydroxide in the presence of an alkali metal hydroxide. 3. The epoxy resin mixture according to claim 1, which has a melt viscosity at 150 ° C. of 0.4 P or less. 4. An epoxy resin composition for powder coating, comprising the epoxy resin mixture according to claim 1 and a curing agent for epoxy resin as essential components. 5. The epoxy resin composition for a powder coating according to claim 4, wherein the curing agent for an epoxy resin is an acid-based curing agent and / or an amine-based curing agent.